1. Field of the Invention
This invention relates to a connector used in wiring of an automobile or the like.
2. Related Art
In a conventional connector of this type, when a metal terminal having a wire connected thereto is to be inserted into and retained on a connector housing, the metal terminal is retained by an elastic retaining piece formed on the connector housing, thereby preventing rearward withdrawal of the metal terminal. A retainer attached to the connector housing prevents an accidental movement of the elastic retaining piece, so that the metal terminal can be held stably.
Namely, the retainer engages the elastic retaining piece to limit the movement of this elastic retaining piece. There is also known a connector of the type in which projections formed on a retainer are engaged with retaining projections formed at a retainer fitting portion in such a manner that the retainer is retained provisionally and completely.
For example, a conventional retainer 104 shown in FIG. 11 includes relatively short lock arms 110b each having a completely-retaining projection 111b, and relatively long lock arms 110a each having an extension portion 113 and a provisionally-retaining projection 111a. A prevention piece 112a is provided between the adjacent short and long lock arms.
Another conventional example of a similar construction shown in FIGS. 12 to 14 is disclosed in Japanese Utility Model Unexamined Publication No. 4-24271.
FIG. 12 is a perspective view of a connector retainer 104 used in a conventional relay block housing, FIG. 13 is a cross-sectional view showing a condition in which the retainer 104 is provisionally retained on the housing 101, and FIG. 14 is a cross-sectional view showing a condition in which the retainer 104 is completely retained on the housing 101.
This retainer 104 includes a prevention piece 112a for limiting the movement of an elastic retaining piece 107a, and a relatively short lock arm 110b having a projection 111b, and a relatively long lock arm 110a having an extension portion 113 and a projection 111a, these lock arms serving to retain the retainer on the housing 101 provisionally and completely.
When the retainer 104 is to be provisionally retained, the projection 111b of the lock arm 110b engages an upper surface of a projection 109b on an inner wall 105b whereas the projection 111a of the other lock arm 110a engages a lower surface of a projection 109a on an inner wall 105a, thereby provisionally retaining the retainer 104, as shown in FIG. 13.
When the retainer 104 is to be completely retained, the projection 111b of the lock arm 110b engages a lower surface of the projection 109b of the inner wall 105b, thereby completely retaining the retainer 104, as shown in FIG. 14.
Here, even if the retainer 104, inverted in a right-left direction, can be attached to the housing 101, the projections 109a and 109b, as well as the projections 111a and 111b, are disposed asymmetrically, and therefore the retainer will not function properly.
In each of the above conventional constructions, the conventional retainer has the lock arms of different lengths which are used as the retaining portions for provisional and complete retaining purposes, respectively. Namely, the retainer is engaged by the lock arms separate from the elastic retaining piece for retaining a metal terminal, and the lock arms are asymmetrical right and left.
Because of this right-left asymmetrical arrangement, in a step of attaching the retainer to the connector housing particularly in the former conventional example, the retainer has often been inserted into the housing in a reverse manner, thus inviting a problem that the efficiency of the operation has been low.
Particularly in the latter conventional example, the retainer can not be of a small size because of its complicated construction, and therefore there has been encountered a problem that a mold is costly.
Furthermore, in either of the conventional examples, the prevention piece for limiting the movement of the elastic retaining piece is interposed between the lock arms through narrow slits, and therefore it has been difficult to withdraw an erroneously-attached metal terminal. Namely, for effecting such a terminal withdrawing operation, a terminal withdrawing jig is inserted into the connector housing through the slit from the retainer side after the retainer is brought into the provisionally-retained position, and then the elastic retaining piece is elastically deformed by it. However, when the jig is inserted, the prevention piece becomes obstructive, so that it has been difficult to elastically deform the elastic retaining piece. If the jig is forcibly inserted, the connector housing or other portion is gouged.
Further For example, in a connector assembly (FIG. 22 shows a perspective view of this connector) as disclosed in Japanese Utility Model Unexamined Publication No. 4-85670, elastic retaining pieces 214A and 214B are provided in a connector housing 210, and inserted metal terminals 230 are retained by the elastic retaining pieces, respectively, and then electrodes 221 of a fuse element 220 are fittingly connected to electrodes 232 of the metal terminals 230, respectively.
The metal terminal 230 is inserted into the connector housing 210 from a lower end thereof, and is moved or pushed upward, and at this time the electrode 232 contacts the elastic retaining piece 214B to elastically deform the same in a right-hand direction in the drawings, and further moves upward. Then, when the metal terminal 230 reaches a predetermined position, a projected portion of the elastic retaining piece 214B becomes engaged in a retaining hole 231 disposed beneath the electrode 232, so that the elastic retaining piece 214B is restored from its elastically-deformed condition into an initial condition.
However, even after the metal terminal 230 is retained as described above, it is possible that the elastic retaining piece 214B is elastically deformed, for example, by an impact applied during the movement of an automobile having the connector mounted thereon. In such a case, there has been a risk that the retaining of the metal terminal 230 is released, so that the metal terminal 230 is disengaged, or an imperfect contact occurs.
Therefore, there has been proposed a construction in which after a metal terminal is retained, a prevention piece, called a retainer, is inserted into a space in which an elastic retaining piece is elastically deformed, thereby preventing the elastic deformation of the elastic retaining piece after the metal terminal is properly retained. For example, Japanese Utility Model Unexamined Publication No. 3-103572 discloses a retainer of the multi-interconnecting type comprises a plurality of flat plate-like base portions 212A interconnected by connecting portions 211. FIG. 23 is a top plan view of this retainer in its attached condition, and FIG. 24 is a front-elevational view thereof.
As shown in FIG. 24, the base portion 212A has two lock arms 210d and 210f formed respectively at opposite ends thereof, and also has a prevention piece 210e. As shown in FIG. 23, this retainer 212 of the multi-interconnecting type is inserted into a connector housing 201 from the upper side, and is retained on the connector housing 201, so that the prevention piece 210e fills in a space in which an elastic retaining piece 214 is elastically deformed, thereby preventing the elastic deformation of the elastic retaining piece.
The retainer 212 is of the multi-interconnecting type, and therefore a plurality of metal terminals are arranged in a row in the connector housing 201, and are retained at a time by the single retainer 212 inserted into the connector housing, thus reducing the cost.
Namely, in this construction, one base portion 212A is associated with one pair of metal terminals. One pair of metal terminals are associated, for example, with one fuse circuit, and therefore one base portion 212A is associated with one fuse circuit.
Therefore, when a defective part needs to be exchanged as a result of checking metal terminals or wires in a fuse circuit, it is necessary to remove the wire or the metal terminal in question. However, in the case of a retainer of the multi-interconnecting type such as the above retainer 212 for retaining the metal terminals of a plurality of fuse circuits, the retaining of all of the metal terminals, associated with this retainer of the multi-interconnecting type, is released when one metal terminal is to be removed. Therefore, the operation for retaining these metal terminals again is cumbersome, and hence the maintenance is very troublesome, and is not desirable.
As described above, although the retainer is effective in retaining the metal terminals in a double manner, the retainer of the multi-interconnecting type has not been suitable from the viewpoint of maintenance.
Therefore, there has been proposed a retainer of the single interconnecting type for facilitating the removable of one metal terminal.
Furthermore, there has been developed a construction in which the retainer is retained in a two-staged manner, that is, in a provisionally-retained condition and a completely-retained condition, for enhancing the efficiency of assembling and maintenance.
The provisional retaining is to tentatively retain the retainer relative to the housing at a stage before the retainer is fully inserted into the housing, in order to enhance the efficiency of the operation such as assembling and maintenance at a factory. The provisionally-retained retainer is held in the housing, with an upper portion thereof disposed in a shallow position in the housing. The connector with the provisionally-retained retainer is shipped to the destination where metal terminal is attached, and the retainer is completely retained.
Namely, the provisionally-retained retainer is further inserted deep into a predetermined position to achieve complete retaining, and the upper portion of the thus completely-retained retainer is received deep in the housing.
In such a construction, during the assembling operation in which the complete retaining is to be effected after the metal terminals are attached, or at the time of effecting an inspection with only the metal terminals removed, the associated retainer is disposed in a shallow position whereas its adjoining retainer is disposed deep.
In the conventional retainer, its upper portion is in the form of a flat plate, and therefore there has been encountered a disadvantage that it is not clear as to whether the retainer to be noted during the operation is disposed shallow or deep.
Therefore, even if the provisionally-retained retainer fails to be shifted or brought into the completely-retained position after the assembling operation or the checking operation, this is often overlooked, and the connector with the provisionally-retained retainer is used, which results in a problem that the metal terminal is disengaged as described above.